Taking a Hay Sample for Your Horse and Understanding the Analysis

Feeding a quality forage should be the basis of every feeding program. Given the forage portion will account for the large majority of nutrient intake for your horse, isn’t it important to understand what is in that forage?

By knowing what is needed to fill in the gaps, you can take the guesswork out of feeding grains, commercial feeds, and supplements to your horse.

Obtaining and knowing how to read a hay analysis is a skill that can help you create the optimal starting point for your horse’s nutrition program.

Taking a Hay Sample

The first step in obtaining a hay sample result is getting a representative sample of your hay. This is best done using a forage probe, which is just one example of the many probes available on the market.

For many horse owners, purchasing a forage probe may not be practical. Local feed stores, agriculture cooperatives or government agencies often have forage probes on hand that can be borrowed.

Ideally, 10-20 individual bales should be sampled to get a representative sample. Smaller sample sizes as few as 2 to 5 can be done as well.

It is important to note that the fewer the samples submitted, the more likely you are to sample an outlier that may not be representative of the batch. This is particularly important in alfalfa/grass blends as the amount of each can vary widely between bales.

Failing any of the above options for obtaining a forage probe, it is possible to take grab samples of forages with a sturdy pair of scissors. Open the bales gently (you do not want to lose the leaf matter in your sample, as horses will preferentially eat this and they are the most likely to fall out of your sample).

Firmly grab a sample out of the slab and use the scissors to cut each side of the hay, so you are left with a handful of hay sample. Drop the hay sample in your ziplock bag and repeat 9 more times on different bales.

Most labs only require about 100 grams of sample for a full analysis, but you should obtain more than that – about 200 grams. Do not exceed 500 grams (about 1 lb) of sample.

Selecting Your Lab for Analysis

With your hay sample secured, now it is time to send the sample off to a certified laboratory. Most forage laboratories will offer an ‘equine’ sample analysis. This is no different in terms of the analysis they do, it is just a tailored report for horse owners.

If you’re going to the trouble of taking the sample, cutting costs will limit the return on your investment. Ensure you get a complete trace mineral analysis by wet chemistry done on your hay sample. For most labs, this will be an extra checkbox and an extra charge.

A hay sample with full analysis with trace minerals by wet chemistry should not cost more than $60.

Unless you want to ‘geek’ out and get a full ruminant analysis done – which will include NDF digestibilities – that will cost more. An example submission form from SGS laboratories in Guelph, ON is shown below. The submission form must be included with your sample.

At Mad Barn, we take the guesswork out of choosing a lab for sample analysis. We partner with two different labs, one in the US and one in Canada, for forage testing that provides a comprehensive analysis for horse owners. Our basic package includes trace minerals, so you don’t have to remember to select this as an add-on service. Additionally, we offer a few other optional analyses to suit each customer’s specific needs.

Below are links to some certified forage laboratories and their respective feed submission forms:

The Next Step: Reading the Analysis

You’ve patiently waited for your hay sample results, now it’s time to go through the report and decipher what they all mean for your horse’s nutrition.

Presented here is a report generated from a sample of first-cut, Ontario hay. This particular report is from SGS Laboratories in Guelph, Ontario and the analysis chosen is called “Equine Complete,” which tests for nutrients significant to horses.

If you go through Mad Barn’s forage analysis service, you’ll receive a breakdown of your analysis by one of our expert nutritionists. They will help you interpret the analysis and offer recommendations on how best to balance your horses’ diets with the hay from the sample.

Dry Matter % and Moisture %

Hay is just dried grass, and grass contains a lot of water. Hay will have some amount of moisture in it – typically around 10%. The “dryness” of hay is measured in percent dry matter, so if you have hay with 90% dry matter, the moisture or water content will be 10%.

Ideally, feed hays should have >85% dry matter or <15% moisture. Excess moisture in bales can promote mold formation and spoilage.

When you read the values on your hay analysis, there are typically values on both an “As is/As sampled” and a “Dry basis”.

Often, animal nutritionists use the values on a Dry matter basis due to the variation in the moisture content of feedstuffs. This is why we recommend reading your analysis from the dry basis column, and we will use the Dry matter values in this guide.

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Protein %

Crude Protein %

Protein % is often also referred to as Crude Protein %, and it is an estimate of the total protein content of the hay based on the nitrogen content. Legume hays, such as alfalfa, will contain higher amounts of protein (15-20%) than grass hays (8-14%) like timothy and orchard grass.

The average, mature horse can do well on a hay with 8 – 10% crude protein, whereas growing horses or broodmares in late gestation will require hay that is 12-18%. Hay with less than 8% crude protein may not be sufficient to reach requirements for a mature horse, and supplemental protein may need to be added to the diet.

This particular hay has 12.21% protein, so it would be on the high side for a horse at maintenance and not enough for a lactating mare or young growing foal.

Remember, excess protein in the diet requires extra energy for the horse to metabolize, and is excreted in urine as urea. It is urea that can result in a strong ammonia smell. Ammonia is a strong irritant to the respiratory tract, and it should be every horse owner’s goal to minimize ammonia levels in barns.

For this reason, it is usually recommended to ensure adequate protein to meet that horse’s needs without providing excessive intake.

Soluble Protein %

Soluble Protein %, or SP %, is the soluble fraction of the protein that is readily available to the animal. It contains small amino acid chains and non-protein nitrogen.

In dry hay, SP% should be between 20-35% of the total CP. The soluble protein value is used more in ruminant nutrition, especially when evaluating ensiled feeds, than for evaluation in horse diets.

Non-Protein Nitrogen % (NPN)

Non-protein nitrogen (NPN) refers to nitrogen-containing compounds that are not considered to be proteins, including urea.

In agriculture, non-protein nitrogen is added to animal feed to provide additional nitrogen to the diet of livestock.

However, NPN is of limited to no value to the horse.

ADF-CP%/ADP/ADIP – Acid Detergent Insoluble Protein

This is the amount of protein that is bound to the ADF (insoluble fiber) fraction of the hay. For a more accurate assessment of protein available for utilization by the horse, subtract this value from the crude protein. 12.21-2.21 = 10.00%. In other words, 18.1% of the total crude protein will not be digested by the horse.

This is a close representation of ‘available protein’. To get a more accurate assessment, we would also have to subtract the NPN fraction of the soluble protein as well, but that is well beyond the scope of most nutrition balancing programs.

NDF-CP%/NDP/NDIP – Neutral Detergent Insoluble Protein

As with ADIP, this is the fraction of protein bound to the NDF fraction.

Note: ADIP & NDIP are not given on most common equine forage samples as they are not utilized in most ration balancing. Although the values are important, they are not a key focus of most equine ration formulation.

Plant Carbohydrates

Acid Detergent Fiber (ADF) %

The ADF of a hay is the portion comprised of cellulose and lignin. It gives an estimate of how much energy the horse can derive from the hay.

As lignin content increases, digestibility of cellulose decreases, which lowers the potential energy that is available to the horse. So, a low value means that cellulose is more available to be digested. The DE (digestible energy) value for horses is calculated based on the amount of ADF.

30-40% ADF is a good range for horses and values above 45% may be too fibrous or indigestible for the horse to acquire adequate energy from. This is the common cause of ‘hay belly‘ – feeding hay too high in ADF.

In this case, the ADF is 40.3%, which is a little bit on the higher side, so it may not deliver the nutrients needed for a high-performance horse or a mare at peak lactation but is a sound choice for horses that are at maintenance or doing light work.

Neutral Detergent Fiber (NDF) %

NDF is a measure of insoluble fiber and includes all of the cell wall carbohydrates- lignin, cellulose, and hemicellulose. Lignin is indigestible, but hemicellulose and cellulose can be partially digested by microorganisms in the hindgut.

NDF can be used to estimate forage intake or palatability- the higher the NDF, the less a horse will eat. NDF levels between 40-60% are suitable for horses, but when hays reach NDF values over 65%, it may limit intake and therefore the horse may not be able to obtain sufficient energy for maintenance.

This hay has an NDF value of 56.6%, which is fairly high. It would be good hay to feed to an easy-keeper, where the goal is to make sure the horse is consuming enough roughage to keep the gut moving, but not to provide excess calories.

Lignin %

Lignin is the indigestible component of plant cell walls. This means that even the fibre-digesting hindgut microorganisms are unable to break it down to be used as energy. The lignin in this hay is 7.8%, which is considered moderately high.

Fat

Fat % or Ether Extract (EE)

Hay contains fat in the form of fatty acids. Typically, mixed grass hays contain 1 – 3% fat.

The laboratory process of extracting fat from hay, ether extraction, removes other plant residues (waxes and pigments) that are not ‘true fat’, so it is reported as crude fat. Generally, the true fat content of dry hay is 80-90% of the reported value.

In this case, fat (%) is 1.48%, but the ‘true fat’ content would be 1.33% (90% of 1.48). Most laboratories will not report ‘true fat’ on an equine analysis, but will on a ruminant forage sample.

Sugars and Starches

Balancing sugars and starch in your horse’s diet is a crucial step on the journey towards developing a balanced diet. Most hay analyses for horses will include NFC, WSC, ESC and starch values; it is important to double-check that these will be included in your forage sample.

Non-Fiber Carbohydrate (NFC) %

Non-fiber carbohydrates measures the non-cell wall fraction of carbohydrates. It includes the readily digestible cell contents including sugar, starch and pectin.

NFC is calculated by subtracting the fiber and ash content of the feed from total carbohydrate content.

Water Soluble Carbohydrates (WSC) %
WSC includes forms of sugars stored in plants:

• Simple sugars
• Disaccharides
• Oligosaccharides
• Some polysaccharides
• Fructans and pectins

Ethanol Soluble Carbohydrates (ESC) %

ESC is a portion of WSC and includes mainly monosaccharides, disaccharides, and oligosaccharides (saccharide is just a generic term that could include the sugars fructose or glucose) that are broken down and digested in the small intestine.

This number is often important when looking at diets for horses with insulin resistance and/or chronic laminitis, as it is what will contribute to the glycemic load.

Starch %

Starch is a polysaccharide (long-chain polymer of glucose molecules) that is present in hay at very low levels. It is digested in the small intestine and will also contribute to the glycemic load.

Forages that are very mature can have a lot of seeds and that can significantly increase the starch level of the forage.

Feeding large amounts of starch can cause it to escape digestion and rapidly ferment in the cecum, which can increase lactic acid production and cause dysbiosis.

Non-Structural Carbohydrates (NSC) or Hydrolyzable Carbohydrates (HC) %

Hydrolyzable carbohydrates (HC), commonly known as non-structural carbohydrates (NSC) form the fraction of the hay that is made up of starches and sugars.

The HC value is a calculated value that is useful for evaluating diets for horses sensitive to large amounts of HC in their diet. These include horses with metabolic problems such as insulin resistance, Equine Metabolic Syndrome or Polysaccharide Storage Myopathy.

Horses like these require a ration that is limited in starch and sugar and should be fed hay with an HC concentration below 10%. HC can be calculated as ESC + Starch from the dry matter column.

HC represents one of the most misunderstood values in horse nutrition. This is due to the fact that most laboratories report HC as WSC + Starch, which is used in ruminant nutrition.

The difference between WSC and ESC (in this case 2.47%) represents fructans and pectins in the hay. These are not digestible in the small intestine and do not contribute directly to glycemic load. However, they are rapidly fermented in the hindgut.

NSC calculated for the purposes of horse nutrition is: ESC + Starch = HC

Further, ESC and starch is more accurately calculated via wet chemistry, which may be an add-on selection and charge for the lab. Nonetheless, it is recommended to select this option if you have horses with underlying metabolic concerns to receive the most accurate numbers.

Minerals

All of the minerals reported on a hay analysis are essential nutrients necessary for overall health and must be available in the diet in adequate quantities to reach daily requirements.

Some ratios of these minerals are particularly important to note due to their relationship with other minerals.

Ash %

The ash content of a forage is just what you might think it is. When the hay sample is burned at very high temperature, what is left is the ash %, which is a gross measure of all the minerals present in the hay.

Sodium %

Hay contains very small amounts of sodium. According to the NRC, 2.4% sodium is the maximum tolerable intake, and this hay contains only 0.09%.

Access to free choice loose salt and fresh water should be available to horses, at all times, so that horses can attain their requirements.

Iron (ppm)

Most forages are naturally high in iron, and this hay contains 255.69 ppm (mg/kg) of it. The max tolerable limit for iron is 500 ppm.

Extremely high iron can interfere with the absorption of other minerals like copper and zinc, so it should be balanced accordingly with a proper mineral and vitamin premix.

Ca:P Ratio

Calcium and phosphorus are the main structural components that makeup bones and teeth. The ideal ratio of calcium to phosphorus is >1.5:1 & <4:1, which means that there needs to be more calcium than phosphorus in hay to maintain this ratio.

The Ca:P ratio of this hay is 2.89, meaning that there is almost 3 times as much calcium as phosphorus, making this hay balanced in terms of calcium and phosphorus.

Ratios are important, but total intake also needs to be considered to ensure adequate intake of each nutrient.

In this case, the hay is 0.29% P. At an intake of 10 kg of hay per day, the horse would be consuming 29 grams of P, which would be more than adequate for most classes of horses.

Zn:Cu Ratio

Zinc and copper have crucial roles in the functioning of many enzyme pathways and in protein synthesis. Two very important proteins that zinc and copper help synthesize are keratin and collagen, which make up hoof and hair tissue.

The Zinc:Copper ratio is ideally at 4-3:1. This hay is at 7.15, so more copper will need to be supplemented in order to reach an appropriate Zn:Cu ratio.

Selenium (ppm)

Most labs do not report selenium, but may offer selenium testing as an add-on. Most forages in North America are presumably low in selenium and additional supplementation is generally recommended.

Soils in Central and Southwest US are considered selenium-adequate, so confirming the selenium level in the hay is important to determine if additional supplementation is warranted.

Molybdenum (ppm)

Some forage reports include molybdenum. The essentiality of molybdenum has not been studied in horses, but it is considered important in other livestock species, which is why it is often included as part of the trace mineral panel.

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Energy

Total Digestible Nutrients (TDN)

Today, TDN is rarely used in equine nutrition. It is used to assess the total digestibility of the forage.

Digestible Energy (DE) (Mcal/kg)

Digestible energy is a measure of calories that are in the hay, and therefore a hay’s energy content. It is most commonly expressed as Mcal/kg, or megacalories per kilogram.

Oftentimes, the DE value will show up on an equine hay analysis as “Horse DE,” depending on the lab analyzing the sample. This is because the DE values of forages for horses are around 15% lower than that of cattle since horses utilize fiber less efficiently than cattle.

This hay contains 2.08 Mcal/kg hay. A 500 kg horse, at maintenance, requires an average of 16.7 Mcal of DE daily (1). A horse consuming 2% of its body weight of this hay (10 kg) would then receive 20.8 Mcal per day, which exceeds this horse’s daily requirement. This horse would be expected to gain weight if given this hay ad-lib (free choice access).

Digestible Energy is a crude measure of energy. It is up to each individual horse owner to monitor the body condition of their horse to determine if more or fewer calories are needed.

Frequently Asked Questions

Here are some frequently asked questions about hay analysis for horses:

Summary

Understanding hay analysis helps horse owners identify protein, fiber, carbohydrate, mineral, and energy levels in forage. Accurate sampling and interpretation ensure diets are balanced and health risks minimized.

• Representative sampling from 10–20 bales provides accurate results to help prevent skewed data
• Certified forage labs offer equine-specific reports, with wet chemistry enhancing mineral accuracy
• Dry matter above 85% ensures hay is stable and prevents mold or spoilage issues
• Sugar and starch levels influence glycemic load and are critical for horses with metabolic issues
• Calcium to phosphorus ratios between 1.5:1 and 4:1 support bone and overall nutrient balance
• Work with a qualified equine nutritionist to develop a tailored feeding plan for your horse